A process for the separation of normal paraffins from a hydrocarbon mixture using a molecular sieve.

摘要

969,353. Absorption-desorption cycles for gas separation. BRITISH PETROLEUM CO. Ltd., A. A. YEO, and R. T. L. MOWLL. Oct. 23, 1962 [Nov. 3, 1961], No. 39433/61. Drawings to Specification. Heading B1L. [Also in Division C5] In a cyclic absorption-desorption process using one or more fixed beds of absorbent for separating gases, e.g. hydrocarbons, the switching of an outlet valve or valves to collect the next effluent from a bed is delayed beyond the switching of an inlet valve or valves to change the feed to the bed so that material present in the void between absorbent particles when the inlet valves are switched is removed from the absorber before the outlet valves are switched in an amount up to 90%. An intermediate purge step may be employed to give an absorption-purge-desorption cycle, and four beds may be used so that at any given time one bed is absorbing, one is being purged and two are being desorbed. The process is described in relation to the separation of n-paraffins from C 4 -200 ‹C. and 200-400 ‹C. B.P. petroleum distillate fractions with 5Š molecular sieve particles isothermally and isobarically at 200- 600 ‹C. and 0-500 p.s.i.g. using nitrogen as purge gas and n-butane or n-pentane, diluted if desired with nitrogen, as desorption gas.